#define N 16
typedef int fix_matrix[N][N]; 

//计算矩阵A的第i行 与 矩阵B的第j列的内积
int matrix(fix_matrix A, fix_matrix B, long i, long k){
    long j;
    int res = 0;

    for ( j=0; j<N; j++ )
        res += A[i][j] * B[j][k];

    return res;
}